Mettlesome is an adjective that means full of vigor and stamina.
The root of our word of the day is mettle M-E-T-T-L-E. a 16th century, variation of metal — M-E-T-A-L, that means the same thing, but used in a more figurative sense. For example, a soldier’s mettle — with two Ts — refers to his courage and stamina.
At first I worried about how our team would face adversity. But I soon discovered that we were a mettlesome bunch.